Identification of Lignin and Polysaccharide Modifications in Populus Wood by Chemometric Analysis of 2D NMR Spectra from Dissolved Cell Walls

Abstract

2D 13C-(1)H HSQC NMR spectroscopy of acetylated cell walls in solution gives a detailed fingerprint that can be used to assess the chemical composition of the complete wall without extensive degradation. We demonstrate how multivariate analysis of such spectra can be used to visualize cell wall changes between sample types as high-resolution 2D NMR loading spectra. Changes in composition and structure for both lignin and polysaccharides can subsequently be interpreted on a molecular level. The multivariate approach alleviates problems associated with peak picking of overlapping peaks, and it allows the deduction of the relative importance of each peak for sample discrimination. As a first proof of concept, we compare Populus tension wood to normal wood. All well established differences in cellulose, hemicellulose, and lignin compositions between these wood types were readily detected, confirming the reliability of the multivariate approach. In a second example, wood from transgenic Populus modified in their degree of pectin methylesterification was compared to that of wild-type trees. We show that differences in both lignin and polysaccharide composition that are difficult to detect with traditional spectral analysis and that could not be a priori predicted were revealed by the multivariate approach. 2D NMR of dissolved cell wall samples combined with multivariate analysis constitutes a novel approach in cell wall analysis and provides a new tool that will benefit cell wall research.

Naturally p-Hydroxybenzoylated Lignins in Palms

“…Several low molecular mass cross-coupling products γ-acylated with p-hydroxybenzoate were isolated from actively lignifying poplar xylem [29,32]. Enhanced interest in p-hydroxybenzoates has surfaced in conjunction with reduced lignification in aspen and poplar following down-or upregulation of genes in the monolignol pathway [38][39][40][41].…”

Chemical profiling of complex biochemical mixtures from various seaweeds

“…Furthermore, the seaweed biomass profiles were largely different from those of land plants. 14,15 Thus, the chemical components of seaweed observed here might reflect the evolution of plants because the evolutionary distance of brown algae from land plants is greater than that of the other algae. 28,29 Taken together, these profiling strategies for describing the water-soluble, water-insoluble and solidstate components of seaweed were capable of evaluating the individual characteristics of different types of seaweed.…”

“…[6][7][8][9][10][11][12][13] In addition, an NMR-based metabolomics approach has been applied to biomass profiling for land plant cell wall components. 14,15 However, biomass profiling of water-soluble and water-insoluble (cell wall) components in diverse seaweeds has been largely unexplored in terms of using the comprehensive characterization afforded by an NMR-based metabolomics approach.…”

An Institutional Approach to Solar Fuels Research

“…[24,35,[46][47][48][49][50][51][52][53][54][55] Bio4Energy is led by Stellan Marklund and is funded with 20 million euros by the Swedish government for the initial 5-year period 2010-14. Further constellations at Umeå University that deal with forest feedstock optimization include Formas-financed Strong Research Environments BioImprove (2.5 million euros) and FuncFiber (2.5 million euros), [56][57][58][59][60][61][62][63] the Wallenberg-financed Conifer Genome Consortium (7.5 million euros), and the UPSC Berzelii Centre for Forest Biotechnology (10 million euros) [47,64,65] financed by the Swedish Research councils VR and Vinnova.…”